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Vector Packet Processing
queue.h
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1 /*
2  *------------------------------------------------------------------
3  * svm_queue.h - shared-memory queues
4  *
5  * Copyright (c) 2009 Cisco and/or its affiliates.
6  * Licensed under the Apache License, Version 2.0 (the "License");
7  * you may not use this file except in compliance with the License.
8  * You may obtain a copy of the License at:
9  *
10  * http://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing, software
13  * distributed under the License is distributed on an "AS IS" BASIS,
14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15  * See the License for the specific language governing permissions and
16  * limitations under the License.
17  *------------------------------------------------------------------
18  */
19 
20 #ifndef included_svm_queue_h
21 #define included_svm_queue_h
22 
23 #include <pthread.h>
24 
25 typedef struct _svm_queue
26 {
27  pthread_mutex_t mutex; /* 8 bytes */
28  pthread_cond_t condvar; /* 8 bytes */
29  int head;
30  int tail;
31  volatile int cursize;
32  int maxsize;
33  int elsize;
34  int consumer_pid;
35  int producer_evtfd;
36  int consumer_evtfd;
37  char data[0];
38 } svm_queue_t;
39 
40 typedef enum
41 {
42  SVM_Q_WAIT = 0, /**< blocking call - best used in combination with
43  condvars, for eventfds we don't yield the cpu */
44  SVM_Q_NOWAIT, /**< non-blocking call - works with both condvar and
45  eventfd signaling */
46  SVM_Q_TIMEDWAIT, /**< blocking call, returns on signal or time-out -
47  best used in combination with condvars, with
48  eventfds we don't yield the cpu */
50 
51 /**
52  * Allocate and initialize svm queue
53  *
54  * @param nels number of elements on the queue
55  * @param elsize element size, presumably 4 and cacheline-size will
56  * be popular choices.
57  * @param pid consumer pid
58  * @return a newly initialized svm queue
59  *
60  * The idea is to call this function in the queue consumer,
61  * and e-mail the queue pointer to the producer(s).
62  *
63  * The vpp process / main thread allocates one of these
64  * at startup; its main input queue. The vpp main input queue
65  * has a pointer to it in the shared memory segment header.
66  *
67  * You probably want to be on an svm data heap before calling this
68  * function.
69  */
70 svm_queue_t *svm_queue_alloc_and_init (int nels, int elsize,
71  int consumer_pid);
72 svm_queue_t *svm_queue_init (void *base, int nels, int elsize);
73 void svm_queue_free (svm_queue_t * q);
74 int svm_queue_add (svm_queue_t * q, u8 * elem, int nowait);
75 int svm_queue_add2 (svm_queue_t * q, u8 * elem, u8 * elem2, int nowait);
77  u32 time);
78 int svm_queue_sub2 (svm_queue_t * q, u8 * elem);
79 void svm_queue_lock (svm_queue_t * q);
80 void svm_queue_unlock (svm_queue_t * q);
82 int svm_queue_add_nolock (svm_queue_t * q, u8 * elem);
83 int svm_queue_sub_raw (svm_queue_t * q, u8 * elem);
84 
85 /**
86  * Wait for queue event
87  *
88  * Must be called with mutex held.
89  */
90 void svm_queue_wait (svm_queue_t * q);
91 
92 /**
93  * Timed wait for queue event
94  *
95  * Must be called with mutex held.
96  *
97  * @param q svm queue
98  * @param timeout time in seconds
99  * @return 0 on success, ETIMEDOUT on timeout or an error
100  */
101 int svm_queue_timedwait (svm_queue_t * q, double timeout);
102 
103 /**
104  * Add element to queue with mutex held
105  * @param q queue
106  * @param elem pointer element data to add
107  */
108 void svm_queue_add_raw (svm_queue_t * q, u8 * elem);
109 
110 /**
111  * Set producer's event fd
112  *
113  * When the producer must generate an event it writes 1 to the provided fd.
114  * Once this is set, condvars are not used anymore for signaling.
115  */
117 
118 /**
119  * Set consumer's event fd
120  *
121  * When the consumer must generate an event it writes 1 to the provided fd.
122  * Although in practice the two fds point to the same underlying file
123  * description, because the producer and consumer are different processes
124  * the descriptors will be different. It's the caller's responsibility to
125  * ensure the file descriptors are properly exchanged between the two peers.
126  */
128 
129 /*
130  * DEPRECATED please use svm_queue_t instead
131  */
133 
134 #endif /* included_svm_queue_h */
135 
136 /*
137  * fd.io coding-style-patch-verification: ON
138  *
139  * Local Variables:
140  * eval: (c-set-style "gnu")
141  * End:
142  */
void svm_queue_unlock(svm_queue_t *q)
Definition: queue.c:103
void svm_queue_lock(svm_queue_t *q)
Definition: queue.c:97
int svm_queue_add_nolock(svm_queue_t *q, u8 *elem)
Definition: queue.c:192
void svm_queue_set_consumer_event_fd(svm_queue_t *q, int fd)
Set consumer&#39;s event fd.
Definition: queue.c:469
int svm_queue_sub_raw(svm_queue_t *q, u8 *elem)
Definition: queue.c:443
void svm_queue_wait(svm_queue_t *q)
Wait for queue event.
Definition: queue.c:151
unsigned char u8
Definition: types.h:56
void svm_queue_add_raw(svm_queue_t *q, u8 *elem)
Add element to queue with mutex held.
Definition: queue.c:220
blocking call, returns on signal or time-out - best used in combination with condvars, with eventfds we don&#39;t yield the cpu
Definition: queue.h:46
svm_queue_t unix_shared_memory_queue_t
Definition: queue.h:132
unsigned int u32
Definition: types.h:88
int svm_queue_sub2(svm_queue_t *q, u8 *elem)
Definition: queue.c:413
svm_queue_t * svm_queue_init(void *base, int nels, int elsize)
Definition: queue.c:33
void svm_queue_free(svm_queue_t *q)
Definition: queue.c:89
int svm_queue_is_full(svm_queue_t *q)
Definition: queue.c:109
int svm_queue_add(svm_queue_t *q, u8 *elem, int nowait)
Definition: queue.c:239
int svm_queue_timedwait(svm_queue_t *q, double timeout)
Timed wait for queue event.
Definition: queue.c:183
svm_q_conditional_wait_t
Definition: queue.h:40
int svm_queue_add2(svm_queue_t *q, u8 *elem, u8 *elem2, int nowait)
Definition: queue.c:289
blocking call - best used in combination with condvars, for eventfds we don&#39;t yield the cpu ...
Definition: queue.h:42
struct _svm_queue svm_queue_t
int svm_queue_sub(svm_queue_t *q, u8 *elem, svm_q_conditional_wait_t cond, u32 time)
Definition: queue.c:348
void svm_queue_set_producer_event_fd(svm_queue_t *q, int fd)
Set producer&#39;s event fd.
Definition: queue.c:463
svm_queue_t * svm_queue_alloc_and_init(int nels, int elsize, int consumer_pid)
Allocate and initialize svm queue.
Definition: queue.c:72
non-blocking call - works with both condvar and eventfd signaling
Definition: queue.h:44